Zusammenfassung

Recently, DNA origami became a powerful tool for custom-shaped functional
biomolecules. In this paper, we present the first approach towards assembling
amphipathic three-dimensional DNA origami nanostructures and assessing their
dynamics on the surface of freestanding phospholipid membranes. Our
nanostructures were stiff DNA origami rods comprising six DNA helices. They
were functionalized with hydrophobic cholesteryl-ethylene glycol anchors and
fluorescently labeled at defined positions. Having these tools in hand, we could
demonstrate not only the capability of the amphipathic nanorods to coat
membranes of various phospholipid compositions, but also their switchable
liquid-ordered/liquid-disordered partitioning on phase separated membranes.
The observed translocation of our nanostructures between different domains was
controlled by divalent ions. Moreover, selective fluorescent labeling enabled us to
distinguish between the translational and rotational diffusion of our six helix
bundles on the membranes by fluorescence correlation spectroscopy. The
obtained data reveal how DNA origami can be employed as a valuable tool in
membrane biophysics.